HESI A2 Cheat Sheet 2026: Every Formula, Conversion & Term You Need

Cramming the night before your HESI A2? Building a long-term study plan? Either way, you need the high-yield facts in one place — the formulas, conversions, prefixes, and rules that show up on the test again and again.

This HESI A2 cheat sheet pulls together the most commonly tested material across Math, Anatomy & Physiology, Biology, Chemistry, Vocabulary, and Grammar so you can review fast and walk into the exam confident. Bookmark this page and come back to it every study session.

Part 1: HESI A2 Math Cheat Sheet

The Math section covers basic operations, fractions, decimals, percentages, ratios, proportions, and — most importantly for nursing — measurement conversions and dosage-style calculations. You'll have a drop-down calculator, but knowing these cold saves precious time.

Essential Conversion Formulas

• Temperature: °F = (°C × 9/5) + 32  |  °C = (°F − 32) × 5/9
• Percent to decimal: move the decimal 2 places left (25% = 0.25)
• Decimal to percent: move the decimal 2 places right (0.4 = 40%)
• Part / Whole × 100 = Percent
• Ratio & proportion: cross-multiply, then solve for x (a/b = c/d → a×d = b×c)

Metric Conversions (memorize the ladder)

• 1 kilogram (kg) = 1,000 grams (g)
• 1 gram (g) = 1,000 milligrams (mg)
• 1 milligram (mg) = 1,000 micrograms (mcg)
• 1 liter (L) = 1,000 milliliters (mL)
• 1 kilometer (km) = 1,000 meters (m)
• 1 meter (m) = 100 centimeters (cm) = 1,000 millimeters (mm)

Household & Standard Conversions

• 1 kilogram = 2.2 pounds (lb)
• 1 inch = 2.54 centimeters
• 1 ounce (oz) = 30 mL (nursing standard)  |  1 fluid oz ≈ 29.57 mL
• 1 cup = 8 oz = 240 mL
• 1 tablespoon (tbsp) = 3 teaspoons (tsp) = 15 mL
• 1 teaspoon (tsp) = 5 mL
• 1 pint = 2 cups  |  1 quart = 2 pints  |  1 gallon = 4 quarts

Roman Numerals (tested on the HESI A2)

• I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000
• Smaller before larger = subtract (IV = 4, IX = 9). Smaller after larger = add (VI = 6, XI = 11).

Military Time

• Midnight = 0000  |  1:00 AM = 0100  |  Noon = 1200  |  1:00 PM = 1300  |  11:00 PM = 2300
• For PM times after noon, add 12 to the hour.

Part 2: Anatomy & Physiology Cheat Sheet

A&P is often the highest-weighted science section and the one nursing programs scrutinize most. Focus on body systems, directional terms, and body cavities.

Directional & Anatomical Terms

• Superior / Inferior: above / below
• Anterior (ventral) / Posterior (dorsal): front / back
• Medial / Lateral: toward the midline / away from the midline
• Proximal / Distal: closer to / farther from the point of attachment
• Superficial / Deep: toward the surface / away from the surface
• Anatomical position: standing, facing forward, palms forward

Body Systems at a Glance

• Skeletal: 206 bones; supports, protects, produces blood cells (hematopoiesis)
• Muscular: 3 types — skeletal (voluntary), cardiac, smooth (involuntary)
• Cardiovascular: heart has 4 chambers; blood flow — vena cava → right atrium → right ventricle → lungs → left atrium → left ventricle → aorta
• Respiratory: gas exchange occurs in the alveoli
• Nervous: CNS (brain + spinal cord) and PNS; neuron is the basic unit
• Digestive: mouth → esophagus → stomach → small intestine → large intestine
• Endocrine: glands that release hormones (pituitary = "master gland")
• Renal/Urinary: nephron is the functional unit of the kidney

Body Cavities

• Cranial: brain  |  Spinal: spinal cord
• Thoracic: heart & lungs  |  Abdominal: stomach, intestines, liver  |  Pelvic: bladder, reproductive organs

Part 3: Biology Cheat Sheet

• Cell theory: all living things are made of cells; cells are the basic unit of life; cells come from existing cells
• Prokaryotic (no nucleus, e.g. bacteria) vs. Eukaryotic (nucleus, e.g. animal/plant cells)
• Key organelles: nucleus (DNA), mitochondria (ATP/energy — "powerhouse"), ribosomes (protein synthesis), ER, Golgi apparatus
• Cellular respiration: glucose + O₂ → CO₂ + H₂O + ATP
• Photosynthesis: CO₂ + H₂O + light → glucose + O₂
• Mitosis = 2 identical body cells; Meiosis = 4 genetically unique sex cells (gametes)
• DNA bases: A–T, G–C  |  RNA replaces T with U (uracil)
• Punnett squares: dominant (capital) masks recessive (lowercase)

Part 4: Chemistry Cheat Sheet

• Atom: protons (+), neutrons (neutral), electrons (−)
• Atomic number = # of protons  |  Mass number = protons + neutrons
• pH scale: 0–14; <7 acidic, 7 neutral, >7 basic (alkaline)
• Bonds: ionic (transfer of electrons) vs. covalent (sharing of electrons)
• States of matter: solid, liquid, gas, plasma
• Matter conservation: matter is neither created nor destroyed in a reaction
• Periodic table: groups = columns (similar properties); periods = rows

Part 5: Vocabulary — Medical Prefixes, Suffixes & Roots

The Vocabulary section mixes everyday academic words with medical terminology. Learn the building blocks and you can decode words you've never seen.

Common Prefixes

• a-/an- = without  |  hyper- = excessive/high  |  hypo- = low/below
• tachy- = fast  |  brady- = slow  |  dys- = difficult/painful
• peri- = around  |  intra- = within  |  inter- = between

Common Suffixes

• -itis = inflammation  |  -ectomy = surgical removal  |  -otomy = incision
• -ology = study of  |  -pathy = disease  |  -emia = blood condition
• -algia = pain  |  -megaly = enlargement  |  -osis = abnormal condition

Common Roots

• cardi/o = heart  |  hepat/o = liver  |  nephr/o & ren/o = kidney
• gastr/o = stomach  |  derm/o = skin  |  oste/o = bone
• neur/o = nerve  |  pulmon/o & pneum/o = lung  |  hem/o = blood

Part 6: Grammar & Reading Cheat Sheet

The 8 Parts of Speech

• Noun (person/place/thing), Pronoun (he, she, it), Verb (action/state)
• Adjective (describes noun), Adverb (describes verb/adjective, often -ly)
• Preposition (in, on, under), Conjunction (and, but, or), Interjection (Wow!)

High-Yield Grammar Rules

• Subject–verb agreement: singular subject → singular verb
• Your (possessive) vs. you're (you are)
• Their (possessive) / there (place) / they're (they are)
• Its (possessive) vs. it's (it is)
• Affect (verb — to influence) vs. effect (noun — a result)
• Fewer (countable) vs. less (uncountable)

Reading Comprehension Strategy

• Identify the main idea first, then supporting details.
• Distinguish fact (provable) from opinion (belief/judgment).
• Watch for the author's tone and purpose (inform, persuade, entertain).
• Answer only from the passage — don't use outside knowledge.

How to Actually Use This Cheat Sheet

A cheat sheet is a review tool, not a study plan. Here's how high scorers use one effectively:

1. Review, then test yourself. Read a section, cover it, and recite it from memory. Passive reading doesn't stick.
2. Turn weak spots into practice. If conversions or prefixes feel shaky, drill them with practice questions until they're automatic.
3. Simulate the real exam. Take timed, full-length practice tests so the format and pacing feel familiar on test day.
4. Track your scores and revisit the sections where you're losing the most points.

The students who score highest aren't the ones who memorized the most facts — they're the ones who practiced under real conditions until recall became second nature.

Frequently Asked Questions

Can I bring a cheat sheet to the HESI A2?

No. The HESI A2 is a proctored exam and outside materials aren't permitted. An on-screen drop-down calculator is provided for the Math section. Use this cheat sheet to prepare — not on test day.

What's the most important section to memorize?

It depends on your program's requirements, but Math conversions and Anatomy & Physiology are the most consistently tested and the most heavily weighted at many nursing schools. Confirm which sections your program requires before you study.

Is memorizing formulas enough to pass?

Memorization gets you partway. The HESI A2 tests application — solving word problems, decoding unfamiliar terms, and answering under time pressure. That's why timed practice questions matter far more than re-reading notes.

How long should I study for the HESI A2?

Most students do well with 4–6 weeks of consistent study. If your test is sooner, a focused 1–2 week plan with daily practice tests can still make a big difference.

Bottom line: Keep this cheat sheet handy for quick reviews — then put it into action with real practice. That's the combination that turns a passing score into a competitive one.